WOW, Lisa!! You're getting a lot of really good tips here! I think you got a really good deal. I don't think you would need a rental car, personally. I usually drive down, but we park our car, unload it, and don't go back to it again until the day we leave!! Disney transportation can't be beat. I've used it almost every trip and it's so nice not to have to worry about parking or even worse, getting out of the parking lot at closing time...flashing back to the 1 time we didn't use it, stayed offsite on New Year's Eve...2 1/2 hrs just to get out of the parking lot! But I digress...Since you have a 4 day Park Hopper, the only suggestion I have is to try EPCOT, maybe the day you go to AK, since it closes early. Illuminations is the wonderful! It's a fireworks show, with a twist! It begins at 9PM at the World Showcase lagoon. There are also a couple of great thrill rides, I notice you like those! Mission Space and Test Track. And there is a neat 3D Movie show, about 15 minutes long, called Honey, I Shrunk the Audience. I'm not sure why you didn't mention wanting to go there, but alot of people think it's just a big science class or something. There are learning opportunities, but more, too. Just an idea. You might want to check out some info sites about the parks to get an idea of what each has to offer. Maybe go check out the park maps site at disneyworld.com?
You will have a wonderful time! Just don't try to do everything, relax and enjoy!!!
Lori